Preston manager Alex Neil believes the Championship must resume at the same time as the Premier League if the season is to be completed.
On Thursday, the Premier League announced a provisional restart date of June 17, with a full round of games taking place on June 19-21, but the return of Championship football is yet to be decided.
Championship clubs are also hoping to resume their campaign next month amid the coronavirus pandemic, but Neil insists they must start playing by June 20 at the latest.
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"I think we're probably going to have to start by June 20 to fit it in," the Preston boss told Sky Sports News.
"We've got nine league games remaining. I'm not quite sure what the play-offs scenario is going to be, but I think to fit the games in we would need to start on the same weekend as the Premier League.
"I think the Premier League deciding on a date is a massive step forward. What we've been searching for as managers is there being a date because if you get a start date you can work yourself back to get your players ready within that period.
Sky to show 64 live PL games - 25 free-to-air
Sky Sports will show 64 live Premier League games, and make 25 available free-to-air when the season resumes
"It's easy to get frustrated because you want to know when your first game is, you want to get your training schedule sorted and the simple fact is those answers can't be provided.
"I think that's a little bit frustrating but I don't think it's anybody's fault. I don't think it's through a lack of effort or through a lack of organisation."
'We want to play all 46 matches'
In case the season has to be ended prematurely, the EFL board "unanimously" agreed upon a framework on Wednesday, but now needs clubs to approve it.
The new framework was laid out on May 21 and included promotion, relegation and play-offs remaining. Clubs will decide whether to change any of these regulations during a meeting on June 8.
Teams in League Two have already indicated they wish to end the season, but League One sides remain undecided.
Neil wants to finish the Championship season by playing the remaining games, even though a potential decision to end the campaign on a points-per-game basis would secure Preston a play-off spot.
"We've very much looking at the fairness and the integrity of the league so we want to play the 46 games," he said.
"If we get the chance to play the games, we'll be ready to play. We're certainly not trying to halt the season, all the way along we've wanted to get back playing so that certainly hasn't changed.
"We're in a good position at the moment and if we deserve to be in the play-offs we'll win enough games between now and the end of the season and if we don't do that then we don't deserve to be there."
Neil: Training's been good, but different
Preston players have been back in training since Monday, with strict protocols in place, and Neil says the squad have returned in good shape after the enforced two-month lay-off.
"It's been good to get back, first and foremost," he said. "I think the lads have spent most of the time sitting in the house and sort of wondering when we're going to get back so I think it's been good for them and it's certainly been good for us to get back on the grass and get some work done.
"All we've really done is break them into groups of five and we've just been putting them through individual drills to keep their fitness levels up and try to recreate things that happen in the match. It's been good, but certainly different."
'Contract discussions are ongoing'
Around 1,400 footballers across the EFL see their contracts expire at the end of June, including six Preston players.
Captain Paul Gallagher and Tom Clarke are two of those whose deals are set to run out, but Neil is confident they will sign beyond June 30 until the remainder of the current season.
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"I would imagine our lads will extend their contracts to the remainder of the season and then when or if we start playing again there will probably be discussions at that point to see whether it's going to be extended or not beyond that," Neil said.
"We have spoke to Paul and Tom in particular because they're two senior players and they've been great servants to Preston, so discussions with them have been ongoing.
"Albeit it's frustrating circumstances that the club finds itself in at the moment, but if we do hopefully get back playing then they'll be other discussions to be had."